I. Field of the Invention
The present invention relates generally to firearms and, more particularly, to a breech assembly for automatic and semiautomatic small arms.
II. Description of Related Art
There are many automatic and semiautomatic small arm rifles that are used both in military applications as well as for civilian use. These previously known automatic and semiautomatic weapons include a bolt which reciprocates between a load position and a firing position for each shot that is fired. In its load position, the bolt is retracted from the barrel which both ejects the casing from the previously fired cartridge and also allows a new cartridge to be loaded from an ammunition magazine into a load chamber behind the gun breech.
The subsequent forward movement of the bolt to its firing position loads the cartridge into the breech and the bolt is then locked into position. Upon firing of the shot, the bolt supports the full load from the firing of the cartridge. After the cartridge has been fired, the bolt unlocks and moves to its retracted or load position in which the casing is ejected, a new cartridge is loaded into the load chamber behind the breech, and the above process is repeated.
Most of today's automatic and semiautomatic rifles use a locking lug style breech to lock the bolt to the rifle when it is fired. In a locking lug style breech, the bolt includes a plurality of radial protrusions that are attached to the bolt. These protrusions pass through mating protrusions on the barrel or barrel extension and the locking lugs and the bolt are then rotated to align with the protrusions on the barrel or barrel extension. Given this geometry, however, the locking lugs can have no more than a 50% load bearing support with the rifle. This, in turn, requires that the bolt as well as the protrusions in the barrel or barrel extension of the rifle have a minimum size in order to adequately support the load when the rifle is fired.